01 400ex Spark Plug

[Pa400exracer]

OK , I HAVE A 2001 400 EX , COMPLETELY STOCK ENGINE , AND WHEN IT SITS FOR OVER LIKE 4 DAYS THE PLUG GOES BAD????WHATS UP WITH THAT

SOO , YA , ID APPRECIATE IT IF ANYONE COULD GIVE ME SOME HELP ON THIS.. ITS GETTIN EXPENSIVE PUTTIN A NEW PLUG IN IT EVERY TIME I WANNA RIDE


THX SO MUCH GUYS/GALS!!!

[ckasper18]

What plug you running dpr8z pump gas or what maybe before parking it turn the gas off and let it run till it shuts off sounds like bad gas.......

[Pa400exracer]

YA, IM RUNNIN A DPR8Z PLUG ON 93 GRADE PUMP GAS

THX MAN

[47501exracer]

what jetting do you have? Maybe that's the problem. Aftermarket silencer or air filter?

[Pa400exracer]

FROM EVERYTHING I KNOW... ITS STOCK JETTING , AND IM RUNNIN A STOCK PIPE WIHT THE SPARK ARRESTER AND EVERYTHING IN IT

[walt miller]

what does the plug look like? is it blackish depossits on it? you could have bad valve stem seals letting oil in and burning up the plug

[Pa400exracer]

its not carbon build up , its like a white color (looks like you just sandblasted it)

[GETWINGS]

i noticed you said you have a modded carb what do you have done to the carb and how cold is it where you live ? alot of time the gas can feeze because of plastic tank or you are not getting enough air and it is fouling a plug. ride red

[Pa400exracer]

oh , i didnt change my sig. yet , for a while , i had the choke out and had a 42 pilot jet in it , but now its back to stock

[GETWINGS]

mine done the same it was running lean .

[Pa400exracer]

right now when i ride its around id say 30-40 , but i keep it outside exposed to the weather , so im thinkin that it might be what you said about the gas

thx for all the help

[Pa400exracer]

ok i guess this weekend when i go ridin ill try settin the carb and see what it does from there

[GETWINGS]

the reason i said it could be the gas is that the tank sweat's and sometimes can freeze here in tenn around dec it got around 15 and my 400 sit in the shop for around 3 weeks with out running it snowed so i got it out and would not start fouled 4 plugs before i took the tank off and poured the gas out put in new rejetted it and has run fine since.

[Pa400exracer]

thx for the help , before i go anywhere far im gonna try and run all of the gas out of it and refill , i think after i run all the fuel out and change the jet setting a bit ill be good to go

i really appreciate you takin the time to reply

*not to start a fight or anything , i was just gonna say that im in my second year of small engine repair and hve been working with quads since like 7th grade , so i know some stuff... just not all**

i never thought about the tank sweating and stuff , but it seems pretty logical to me

[GETWINGS]

your welcome i don't know a hole lot just been there and done that i hope it fix's your problem and any time.:)

[ckasper18]

The only other thing we replace after lots of use is the needle and seat i have been working in parts at my familys honda shop for 25 plus years and we live here in wisconsin cold as hwll and we put a 40 pilot jet in every new 400 ex we sell otherwise they dont start.After tons of use and folks riding with dirty air filters the needle and seat wear out brass on brass moving up and down hundreds of thousands of times start to wear never hurts to replace......................Chris